In a conventional wiring formation for semiconductor devices, it is general that a metal to be formed into a wiring is applied on a silicon wafer to form a film thereof, and the film is shaped into a desired wiring through lithography and dry etching, and thereafter spaces between the wiring are buried with an insulation film to perform the wiring formation. Recently, there has been developed a chemical mechanical polishing with use of both a special polishing agent and a polishing pad, which is hereinafter abbreviated as CMP, as the case may be, and a wiring formation by damascene process utilizing CMP has been paid attention. According to this method, an insulation film is formed first of all, and thereafter, a groove for the wiring is formed through lithography and dry etching, a metal is applied thereto to form a film thereof and bury the groove therewith, and then CMP is carried out to remove the metal film jutted out from the groove.
However, in the metal wiring formation utilizing CMP, both the surface and the back of a wafer are markedly contaminated with the polishing agent remaining after the metal polishing, a polishing scrap produced by the polishing and metal impurities contained in the polishing agent and the polishing pad, and therefore it is inevitable to clean the surface thereof after the polishing.
In general, in order to remove particles present on a wafer surface, it is desired to carrying out a cleaning with an alkaline solution, because it is important to inhibit re-adhesion of particles once removed out of the surface thereof. While, in order to remove metal impurities effectively, it is desired to carry out the cleaning with an acid solution having a strong metal dissolution power.
However, as is known, a metal is subject to corrosion with these alkaline and acid solutions. Therefore, in the case where the wafer surface on which the metal wiring lays bare is cleaned with these solutions, there is usually caused a problem such that the metal surface after the cleaning is subjected to corrosion, thereby causing increase of a wiring resistance and moreover a breaking down of the wiring.
As a corrosion inhibitor to avoid the metal-corrosion, there are known aromatic hydrocarbon compounds such as, for example, benzotriazole and 5-methylbenzimidazole, and an attempt to use these corrosion inhibitors has been made. Meanwhile, an influence upon human health and the ecological system suffered by various chemical substances discharged to surroundings is now examined. Thus, a metal-corrosion inhibitor less than that so far in use in the possibility of affecting human health and the ecologrical system through a water medium is desired to be developed.